Fiber optic cables are widely used to transmit light signals for high speed data transmission. The fiber optic cables include an optical fiber or optical fibers. The optical fibers function to carry the light signals (i.e., optical signals). A typical optical fiber includes an inner core surrounded by a cladding that is covered by a coating.
Fiber optic cable connection systems are used to facilitate connecting and disconnecting the fiber optic cables in the field without requiring a splice. A typical fiber optic cable connection system for interconnecting two fiber optic cables includes fiber optic connectors (i.e., optical fiber connectors) mounted at ends of the fiber optic cables, and an adapter for mechanically and optically coupling the fiber optic connectors together. The fiber optic connectors generally include ferrules that support ends of the optical fibers of the fiber optic cables. End faces of the ferrules are typically polished and are often angled. The adapter includes co-axially aligned ports (i.e., receptacles) for receiving the fiber optic connectors desired to be interconnected. The adapter may include an internal sleeve that receives and aligns the ferrules of the fiber optic connectors when the connectors are inserted within the ports of the adapter. With the ferrules and their associated fibers aligned and abutted within the sleeve of the adapter, a fiber optic signal can pass from one fiber to the next corresponding fiber via an optical interface created by this arrangement. The adapter also typically has a mechanical fastening arrangement (e.g., a snap-fit arrangement, a latch, etc.) for mechanically retaining the fiber optic connectors within the adapter.
A prior art fiber optic connection system is disclosed at U.S. Pat. No. 5,214,730 to Nagasawa et al., issued May 25, 1993, and hereby incorporated by reference in its entirety. Prior art fiber optic connectors include fiber optic connectors that are available from US Conec Ltd. of Hickory, N.C., USA as part numbers C10821, C10822, C8190, and C10823. Fiber optic connectors related to part numbers C10821, C10822, C8190, and C10823 are known as MTP® connectors. Other prior art fiber optic connection systems include SC type fiber optic connectors and adapters, disclosed at U.S. Pat. No. 5,317,663, that is hereby incorporated by reference in its entirety.
FIGS. 6, 8, and 11 generally illustrate certain features of certain MTP® connectors as example connector 100. The example connector 100 includes a plurality of optical fiber termination locations 108 at an end 102 of the connector 100 (see FIG. 8). The end 102 has a generally rectangular shape, and the plurality of the optical fiber termination locations 108 can form one or more rows aligned along a long dimension of the generally rectangular shape. The connector 100 has a somewhat rectangular cross-section, aligned with the generally rectangular shape of the end 102, with a long side 104 and a short side 106 (see FIGS. 8 and 11).
The example connector 100 includes a connector body 110, a release sleeve 130, a ferrule 150, and a pair of alignment pins 160. The connector body 110 extends from a first end 112 to a second end 114. The first end 112 is adapted to be inserted into a port of a fiber optic adapter, and the second end 114 connects directly or indirectly to a fiber optic cable (e.g. a group of optical fibers joined together in a flat ribbon by a polymeric coating). A key 116 can be included on the connector body 110 to properly rotationally orient the connector 100 and the fiber optic adapter when they are joined together (see FIGS. 8, 15, and 17). The example connector 100 includes the key 116 on one of the long sides 104. The connector body 110 can also include grooves 117 (see FIGS. 8 and 11) on one or both of the short sides 106. The grooves 117 can serve to align and rotationally orient the connector 100 and the fiber optic adapter when they are joined together. Latching features (not shown) can be included within the grooves 117 to enable connection of the connector 100 and the fiber optic adapter. A flange 124 can be included at or near the second end 114 of the connector body 110. An interior passage 126 extends through the connector body 110 from the first end 112 to the second end 114 and is adapted to house the optical fibers. An exterior 128 of the connector body 110 can be separated from the interior passage 126 by one or more walls 129 of the connector body 110 (see FIG. 6).
The release sleeve 130 of the connector 100 extends from a first end 132 to a second end 134. The release sleeve 130 is positioned around a portion of the exterior 128 of the connector body 110 with the first end 132 nearer the first end 112 of the connector body 110 and the second end 134 nearer the second end 114 of the connector body 110. A sliding surface 144 (e.g., a slide) of the release sleeve 130 can slidingly engage a sliding surface 118 (e.g., a slide guide) of the connector body 110 and thereby allow the release sleeve 130 to slide on the connector body 110 between a latching position (shown at FIG. 6) and a release position. When the release sleeve 130 is at the latching position and the connector 100 is fully inserted into the fiber optic adapter, the connector 100 is latched to the fiber optic adapter. By moving the release sleeve 130 from the latching position to the release position, the connector 100 is unlatched from the fiber optic adapter and can thereby be removed (i.e., disconnected) from the fiber optic adapter.
The release sleeve 130 is typically biased toward the latching position (e.g., by a spring). FIG. 6 pictorially depicts a first stop 120 on the connector body 110 adjacent a first stop 136 on the release sleeve 130. A spring (not shown) can urge the first stop 136 against the first stop 120 and thereby urge the release sleeve 130 to the latching position. When the release sleeve 130 is moved to the release position, a second stop 122 of the connector body 110 can abut a second stop 138 of the release sleeve 130. The first stop 120 of the connector body 110 can be included on the key 116 (as shown at FIG. 6) or can be a separate feature, and the first stop 136 of the release sleeve 130 can be included at the first end 132 (as shown at FIG. 6) or can be located elsewhere. Likewise, the second stop 122 of the connector body 110 can be included on the flange 124 (as shown at FIG. 6) or can be a separate feature, and the second stop 138 of the release sleeve 130 can be included at a flange 140 (as shown at FIG. 6) or can be located elsewhere.
The example connector 100 defines a central longitudinal axis A1 (see FIGS. 6 and 19). The release sleeve 130 can be slid back and forth relative to the connector body 110 through a limited range of movement that extends in a direction along the central longitudinal axis A1. When the release sleeve 130 is in the latching position, a gap 170 is defined between the second end 134 of the release sleeve 130 and the flange 124.
The ferrule 150 is adapted to hold one or more optical fibers of the fiber optic cable and terminate the ends of the optical fibers at an end 152 (i.e. a terminal end) of the ferrule 150. The end 152 of the ferrule 150 coincides with the end 102 of the connector 100, and the plurality of the optical fiber termination locations 108 are on the ferrule 150 (see FIG. 8).
The ferrule 150 can also include a pin 160 or a pair of the pins 160 that extends to an end 162 spaced from the end 152 of the ferrule 150 and thereby engender the connector 100 as a male fiber optic connector as illustrated at FIG. 6. The ferrule 150 can also include a pin hole or a pair of the pin holes and thereby engender the connector 100 as a female fiber optic connector. The ferrule 150 can also include one pin 160 and one pin hole and thereby engender the connector 100 as a hermaphroditic fiber optic connector (see FIG. 4A of U.S. Pat. No. 6,340,247 to Sakurai et al., issued Jan. 22, 2002).
As shown at FIGS. 27 and 28 of U.S. Pat. No. 5,214,730, when coupled together in a functional configuration, two of the example connectors 100 and the corresponding adapter provide the optical interface protection from contamination. In particular, overlapping fits of the ports of a housing around the connectors 100 provide a layer of protection to the optical interface. When either of the connectors 100 is disconnected from the adapter, the disconnected optical interface is exposed to contamination around the ferrule 150 of the connector 100. The optical interface is sensitive to contamination. If the optical interface is contaminated, the fiber optic signal connection may be disrupted or weakened upon reconnection.
Dust caps have been developed to protect the connector 100, and in particular the ferrule 150, from contamination when disconnected. Such a dust cap is disclosed at U.S. Pat. No. 7,245,813 to Brown et al., issued Jul. 17, 2007, hereinafter referred to as the '813 dust cap. A commercial embodiment of the '813 dust cap is available from US Conec Ltd. of Hickory, N.C., USA as part number C7721. Another such dust cap is also available from US Conec as part number C 10063. Other example dust caps are disclosed at U.S. Patent Application Publication No. 2008/0304804 to Zimmel et al., published Dec. 11, 2008; now U.S. Pat. No. 7,565,053, issued Jul. 21, 2009; U.S. Pat. No. 7,164,840 to Hsieh, issued Jan. 16, 2007; and U.S. Pat. No. 6,712,524 to Beatty et al., issued Mar. 30, 2004.